The present invention relates to a technique for processing a three-dimensional image.
Conventional devices (or programs) for processing two-dimensional images are generally classified into two groups in terms of the way of processing images: one specifies a group of pixels to determine display attributes such as colors, and the other specifies graphical elements such as lines, circles, ellipses, and polygons. With the former technique, a user is allowed to draw and/or delete an image on the screen by means using a composite set of commands or drawing tools as pictorial or iconic representations of, for example, a pencil, a brush, a spray, or an eraser to change the display attribute(s) of the pixels in an area defined on the screen. On the other hand, the latter technique requires the user to specify a graphical element such as a line and a display position thereof rather than specifying the pixels. More specifically, this technique uses several algorithms prepared for respective graphical elements to compute and determine locations of the pixels composing the graphical elements. Specifying the graphical element and the display position thereof causes computation of the pixel locations to draw that graphical element.
The first technique has the advantage of easy-handling with the increased degree of drawing freedom, while the second technique has the advantage of positive and precise drawing of the graphical element. The second technique is, however, rather complicated and cumbersome for uses because no area of which display attribute is changed can be specified directly.
Devices for processing three-dimensional images currently available are only those based on the second technique, i.e., a graphical element is specified and drawn by using algorithms for three-dimensional image drawing. The uses thus cannot draw a three-dimensional image without any limitation by the graphical elements.
The present invention was made with respect to the above mentioned problems, and an object thereof is to achieve three-dimensional drawing of images without specifying a graphical element.